This research is to develop a minimally invasive, percutaneously-placed system that will measure blood flow in the body. Blood flow keeps tissue alive. Sophisticated instruments, such as duplex Doppler, MRI or CT angiography, can measure blood flow noninvasively, but provide only a "snapshot" of the flow. Our goal is to develop minimally invasive percutaneously-placed devices that can provide both acute and long-term reliable, accurate monitoring of blood flow, thus providing new medically significant information about patients'cardiovascular systems. We have previously developed, under NIH sponsorship, an implant unit to operate a surgically implanted flow sensor in an artificial artery, and wirelessly transmit the flow data transcutaneously. Under another NIH-sponsored program, we have learned how to make special flexible ultrasound Doppler transducer systems. In this Phase I, we will measure flow by holding these transducers against the inside wall of an artery with a stent, with signals to and from the transducers carried by a thin, narrow strip lying along the wall. In Phase I, the "intravascular lead" will exit the animal body for signal processing. In the future, for long-term measurements, these signals will connect to an implanted unit for transcutaneous communication. Collaborating with us are an outstanding cardiac surgeon and interventional cardiologist who will perform the surgical studies and advise the team on percutaneously placing stent-devices. The effects of neointimal growth and tissue response on these new components, and any effects of these components on vessel tissue, will be evaluated by a 30-day implant followed by histopathological examination of the vessel. Where flow monitoring has been possible, as in dialysis access grafts and leg bypass grafts, long-term monitoring of flow has significantly improved patient outcomes. The goals of this program are to prove the concept of a new percutaneously placed blood flow measuring system to bring the benefits of flow monitoring to many parts of the circulatory system, potentially greatly improving outcomes for millions of patients. PUBLIC HEALTH RELEVANCE: This research is to develop a minimally invasive implantable device that can provide both short and long-term reliable, accurate monitoring of blood flow, thus providing new medically significant information about a patient's cardiovascular system. Since blood flow keeps tissue alive, it may be possible to prevent failures of blood flow, such as heart attacks, and bring the benefits of flow monitoring to many parts of the circulatory system, significantly improving outcomes for millions of patients.